不要物体推到在JavaScript深或浅拷贝一个数组？ [英] Do objects pushed into an array in javascript deep or shallow copy?

问题描述

pretty言自明的问题......当在JavaScript阵列上使用.push（），是对象推入数组的指针（浅）或实际的对象（深）的无论的类型。

Pretty self evident question...When using .push() on an array in javascript, is the object pushed into the array a pointer (shallow) or the actual object (deep) regardless of type.

推荐答案

这取决于你推什么。对象和数组引用推。内置的类型，如数字推一个副本。

It depends upon what you're pushing. Objects and arrays are pushed by reference. Built-in types like numbers are pushed as a copy.

var array = [];
var x = 4;
var y = {name: "test", type: "data", data: "2-27-2009"};

// primitive value pushes a copy
array.push(x);
x = 5;
alert(array[0]);    // alerts 4 because it's a copy

// object reference pushes a reference
array.push(y);
y.name = "foo";
alert(array[1].name);   // alerts "foo" because it's a reference

这个工作code的演示： http://jsfiddle.net/jfriend00/5cNQr/

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